1. Field of the Invention
This invention relates to apparatus for compressing and buffering large amounts of data in a computer system and more particularly to such apparatus which receives in real time main storage addresses collected by hardware data collection apparatus and transfers the buffered data to slower speed data storage to facilitate address tracing.
This invention finds particular utility in a computer system which operates at relatively high speed and utilizes large main storage addresses such as large virtual storage addresses.
2. Description of the Prior Art
During the design phase of a computer system and after the computer system has been placed into operation, it is often desirable to monitor its operation by collecting data such as main storage addresses. The data collected is useful for design modification and tuning of the computer system. The most desirable arrangement is to collect this data while the computer is operating in a normal manner and to do so with minimum interference with the operation of the computer system. In the past, when possible, a faster computer system with sufficient storage capacity would be used to monitor the slower computer system. That arrangement of course is expensive and not particularly feasible for field use.
Another approach has been to collect only samples of the data being sought. This approach is not suitable when an address trace is required. The present invention permits all main storage addresses to be collected. The apparatus for performing the data collection can be of the type shown and described in the IBM Technical Disclosure Bulletin for Virtual Address Trace Mechanism, page 831-833 dated July 1983 which is more suitable than the arrangement set forth in the IBM Technical Disclosure Bulletin for Virtual Address Monitoring Technique, page 4625, dated May 1977.